The fight against extremists in northern Mali has shifted from full on combat to a phase of hide-and-seek with jihadists, who are outnumbered and avoid direct contact with French troops, the forces say.

The French Operation Serval, launched in 2012, pushed extremists from strongholds in Mali's north. In Operation Barkhane, launched nearly a year ago, French forces have adopted new methods of routing out Islamic extremists, including surveying the desert using drones flying sometimes in 20-hour shifts.

“The security situation is different now,” said Col. Luc Laine in Gao, Mali. The search for jihadists is “highly reliant on intel gathering, research, with lots of waiting around and isolated actions,” he said.

The scale of the operation, which covers a 4,000-kilometer-wide (2,500-mile-wide) span over five countries from Burkina Faso to Chad, allows forces to track down extremists beyond the borders of Mali, where many have taken refuge.

“We need them to be afraid,” says Col. Eric Bometon, the commander of the air detachment. “There are no more highways for them, they have to borrow the beaten tracks, they have to slow down, and that's where we want them,” he says from his base in Niamey, Niger.

Al-Qaida-linked fighters in Mali have resorted to placing mines on the roads, launching deadly ambushes on U.N. peacekeepers in Mali and attacking French bases with rockets.

“It's difficult for us to protect ourselves from that,” says Col. Luc Laine.

About 3,000 French troops, 11,500 U.N. peacekeepers and local armies are chasing extremists estimated to now be no more than a few hundred, according to French military estimates.

But many are thought to have taken refuge in Libya, out of Barkhane's scope. Last week, Barkhane's top commander warned Libya had become an “incubator of terrorism” and called intervention in Libya “a matter of efficiency.”